(1) Field of Invention
This invention introduces the standard rotating bushing in the drilling, the tapping and the combined process of drilling and tapping. The drill, tap and combination drill & tap are the tools that use this invention. The standard rotating bushing guides the standard letter, number and fractional size tools defined by the American National Standards Institute. The standard rotating bushing guides the analogous standard Metric tools, too. The standard rotating bushing sizes are designed to be Catalogue Standard Sizes and identify the standard rotating bushing as ANSI Standard Bushing.
(2) Description of Prior Art
The bushing used in drilling process is single unit. The tool touches the inner wall of it and shaves it during the drilling process, that fact determinate the increasing of the bushing standard interior diameter tolerance. The consequence is that the bushing wears out and must be frequently replaced. It does not exist any standard bushing for the tapping process and the combined process of drilling and tapping.